Improvement in door-locks



c. c. DICKERMAN.

DOOR-LOCK.

Patented Feb. 15,1876.

Pgiflaai:

W W M 5 N. PETERS. PHOTO LIT UNITED STATES, PATENT (Dr-Free. 1

CHARLES c. DIGKEBMAN, or eosron, MASSACHUSETTS.

.IMPR OVEMENT IN DOOR-LOCKS.

Specification forming part of Letters Patent No. 173,450, dated February 15, 157 6 applicationfiled December 13, 1875.

- from the other or opposite side with a knob, .or its equivalent, yet so peculiarly constructed that, although it may be locked and unlocked by the knob on the one side and by the key fromt-he opposite side when locked by the knob, but cannot, if .locked by the key from one side, he thereafter unlocked by the knob from the opposite side.

The construction of a lock which may beoperated from one side with a key only and from the opposite side by a knob isin no sense new,'but is well known and in very geheral use, and greatly admired for the convenience it affords in locking.;and unlocking from the inside without the use of the key.

'Notwithstanding the desirability of constructing locks so as. to be operated with a knob upon. the inside of the building or place secured bythein, there has heretofore been much objection made to such by a multitude of persons who would otherwise' adopt and use them, which objections, as

. raised, are,'that in case any evil-disposed persons should, while the premises provided with such locks are open,- and free to the en:

trance of said persons, enter and secrete themselves on the premises, they may, after the departure'of the persons incharge of said premises, and after the place has been locked from the outside, help themselves to whatever theychoose, and quietly turn the knob -from the insideand depart; also,that where glass is used in doors, the same may beeasily broken, thehand passed through the aperture,

and the lock easily opened.

My invention, it will be seen, obviates all A possibility to any like occurrence, and, in

fact, when a lock is constructed with my improvement, it affords far greater security with .my improvement.

than when made with a key-hole in each side, for the reason that if the lock is locked with the key from the outside it cannot possibly -be unlocked or picked from the inside.

Figure 1 represents an interiorview of the lock, with bolt and other parts necessary for the proper operation thereof, constructed Fig. 2 represents a section on line as x of Fig. 1. Fig. 3 shows the bolt of the lock with its proper projections and slots, hereafter more fully described. Fig. 4 represents the main dog orgstop-lever with its necessary appliances. Fig. 5 represents the auxiliary or safety dog-lever and appliances. Fig. 6 shows two views of the inner or knob trunnion and its knob. Fig. 7 shows three views of the outside trunnion i, with keyslot therein.

In describing my invention it is deemed unnecessary to enter into a general descrip tion of the construction of the lock, only so much thereof as relates directly to the subject of my claims, and I therefore omit all foreign matter.

Fig. 8 shows the bolt B as thrown out by the action ofthe knob-trunnion T, and secured in this position by the combined action of the lug N of the dog 1) against the projection K on the shell A and the spring W,

when the safety-dog '1) 'is brought in position with the inside of its lug M bearing directly against the outer side of the projection K, in which position it is free to be operated by the action of the inside knob-trunnion T.

Fig. 9 shows the bolt B. thrown out by means of the outside or key trunnion 'i, one of the arms of which, it will be seen, passes directly over the face'of the safety-dog D, thus leaving the latter in the position held by its spring U, which allows its lug M to always pass above the projection K, by which operation and action the safety-dog D is held firmly in position against the side of the knob-trunnion T, thus preventing the possibility of turn- ,ing the knob-trunnion T until released-from its confinement by the operation of the keytrunnion '11 upon the lug F of the dog D, and the throwing back ofthe bolt B, by which action the safety-dog D is again left free to be operated by the knob-trunnion T.

Having thus described myinvention, what I nions 'I and i, or their equiyaient, substantiailesire to claim, and secure by Letters Patent, 15 as and for the purpose described. 15-

lpThe combination of the safety-dog D CHAS. G. DIOKERMAN. with the bolt B and projection K, orits equivalent. Witnesses:

2. The combination of the dogs D and D, GEORGE PENNIMAN, the bolt B, shell A, and springs with the trun- A. G. BURTON. 

